AIR FILTER

PROBLEM TO BE SOLVED: To provide an air filter that is hard to crush at the time of ventilation or dust loading, has excellent dust holding property, and has excellent resistance against possible entry of moisture, such as paint.SOLUTION: An air filter of the present invention is a laminate of a pleat structure and a planar reinforcement material, and a trough part of the pleat structure and the reinforcement material are integrally adhered. The pleat structure is formed from a needle punch nonwoven fabric in which a first fiber having a melting point of 80°C-200°C is cross-connected with a wound-contracted second fiber having a hollow structure and having a melting point 30°C or more higher than that of the first fiber, and the second fiber is fused by a melting-coagulation part composed of a part or the whole of the first fiber. Alternatively, the pleat structure is formed from a nonwoven fabric in which a first fiber having a melting point of 80°C-200°C is cross-connected with a wound-contracted second fiber having a hollow structure and having a melting point 30°C or more higher than that of the first fiber, and the second fiber is fused by a melting-coagulation part composed of a part or the whole of the first fiber, and a fiber orientation degree in thickness direction is from 20° to 50°.SELECTED DRAWING: Figure 1 【課題】本発明の目的は、通風時やダスト負荷時に潰れにくく、ダスト保持性にも優れ、かつ塗料等の水浸入時耐性にも優れるエアフィルタを提供することにある。【解決手段】本発明に係るエアフィルタは、プリーツ構造体と平面状補強材との積層体であり、前記プリーツ構造体の谷部と前記補強材が接着一体化されていることを特徴とする。前記プリーツ構造体は、融点が８０℃以上２００℃以下である第１繊維と、融点が前記第１繊維よりも３０℃以上高い中空構造を有し且つ捲縮した第２繊維とが交絡し、前記第１繊維の一部または全部からなる溶融凝固部によって第２繊維が融着されたニードルパンチ不織布、或いは、融点が８０℃以上２００℃以下である第１繊維と、融点が前記第１繊維よりも３０℃以上高い中空構造を有し且つ捲縮した第２繊維とが交絡し、前記第１繊維の一部または全部からなる溶融凝固部によって第２繊維が融着され、厚さ方向への繊維配向度が２０°以上５０°以下である不織布から構成される。【選択図】図１